This invention concerns a machine to produce espresso coffee as defined in the main claim.
To be more exact, the invention concerns a machine of the type able to produce espresso coffee by using pre-packed portions based on coffee powder.
The state of the art includes machines to produce espresso coffee, generally for use in the home, which use pre-packed portions of coffee powder.
The pre-packed portions are used once and normally consist of pressed wafers wrapped one by one in paper wrappers, or of plastic capsules containing the coffee powder.
Conventional machines to produce espresso coffee generally comprise a water tank associated with a delivery circuit co-operating with pump means and with instantaneous heating means.
The delivery circuit is associated at the ends with an infusion chamber in which there is a seating able to contain at least one of the said pre-packed portions.
The infusion chamber is defined by two reciprocally movable sides able to assume a first open position, wherein they allow the pre-packed portion to be introduced and removed before and after the coffee-preparation cycle, and a second closed position wherein they enclose the pre-packed portion during the preparation of the coffee.
The infusion chamber is also associated at the lower part with a delivery channel by means of which the coffee produced flows into the container used to drink it (cup, glass, etc.).
To prepare the espresso, the user inserts a pre-packed portion inside the infusion chamber and arranges the two parts of the latter in the closed position; then, by acting on the appropriate commands, he/she begins the preparation of the espresso.
During this step, the pump means take the necessary quantity of water from the tank and send it to the delivery circuit, where it is taken to the correct temperature by the instantaneous heating means.
The hot water is then sent under pressure inside the infusion chamber where it passes through the pre-packed portion, emerging from the delivery channel in the form of espresso coffee.
When the coffee has been delivered, the infusion chamber is opened to allow the used pre-packed portion to be removed so as to prepare the machine for a new coffee-preparation cycle.
In conventional machines the main functional disadvantages are, firstly, to correctly perform the operation to insert and remove the pre-packed portions into/from the infusion chamber and secondly, that the opening and closing of the latter is not very practical.
The pre-packed portions, in fact, have to be introduced into the infusion chamber in a completely manual manner, without the aid of guide and centering means, and therefore they may be positioned incorrectly or inaccurately, thus compromising the subsequent closing of the infusion chamber.
The correct positioning of the portions is also made problematical by the location of the infusion chamber, which is often made in very restricted spaces and is difficult to access.
It is also difficult to remove the used pre-packed portion, both because it tends to remain attached to one of the parts of the infusion chamber, and also because at the end of the operation to prepare the coffee it is still very hot and can burn the hands of whoever tries to remove it.
In some machines, the lower part of the infusion chamber is associated with a removable support; although this embodiment makes it easier to insert and remove the pre-packed portion, it entails the difficulty that the support itself is difficult to remove and re-assemble.
When the support is re-assembled, moreover, there is the risk that the pre-packed portion may be displaced which can therefore be incorrectly arranged and centered when the infusion chamber is closed.
The infusion chamber too is usually opened/closed manually and this may also entail, if performed incorrectly, an incorrect functioning of the machine.
Document EP-A-784.955 describes an espresso coffee machine comprising a box-like container inside which is housed a supporting plate able to rotate, during use, around a vertical axis.
The rotary plate is suitable to define a plurality of seatings for individual portions of coffee; as it rotates, it causes the sequential positioning of the portions of coffee respectively in a loading station, a working station where the portion is hit by a flow of hot water to obtain the coffee, and a station to discharge the used portion.
This solution is characterised by the fact that it is very bulky because it has three angularly different positions wherein the three operating steps take place.
It is rather complicated for the user to insert the new portion of coffee into the loading seating, which must be done in narrow, limited spaces, by opening and closing a sliding door.
Moreover, the mechanism which advances the rotary plate is complex, and easily subject to breakage and wear.
The fact that several portions of coffee are kept inside the machine after use may cause humidity and bad smells.
The mechanism to expel the used portions is also rather complicated.
Moreover, the machine does not provide to generate steam only.
Document DE-A-196 47 039 shows a machine to produce coffee comprising a boiler head movable upwards to facilitate the operations to load the portion of coffee and a little cup which can be moved on a horizontal plane after the boiler head has been raised.
This solution in no way solves the problem of discharging the used coffee portion, nor does it make it easy to carry out the operations to position and center the individual portions on the relative seating in the cup.
Moreover, it does not provide automatic means, co-ordinated with the start of the cycle to produce the coffee, to ensure that the two parts of the infusion chamber, upper and lower, are hermetically sealed.
Furthermore, this machine does not provide the possibility to generate steam only.
EP-A-334.571 and EP-A-041.931 discloses coffee machines having means to remove the used coffee portion; however, they do not disclose or suggest means able to automatically remove said used portion, after the delivery of the coffee, during the withdrawal movement of the lower part of the machine from an inner working position to an outer loading position, consistently and inherently with this movement, to clear out the positioning seating and allow at once to an user the loading of a new portion in this seating.
The present Applicant has devised and embodied this invention to overcome these shortcomings, and to obtain further advantages.
The invention is set forth and characterised in the main claim, while the dependent claims describe other characteristics of the main embodiment.
The purpose of the invention is to provide a machine to produce espresso coffee, of the type able to use pre-packed portions of coffee powder, which will be economical and easy to use, which will facilitate the operations to position and remove the pre-packed portions and wherein the opening and closing of the infusion chamber will be achieved automatically.
Another purpose of the invention is to achieve a machine to produce espresso coffee with a structure which can easily be reconfigured to use pre-packed portions of different types and packaging.
A further purpose is to achieve a machine wherein the infusion chamber is hermetically sealed automatically in a manner coordinated with the performance of the cycle to produce the coffee.
Another purpose of the invention is to ensure that the portion is automatically discharged after every cycle to prepare the coffee, and also to ensure that the portion is always accurately positioned and centered in the relative seating, inside the infusion chamber.
The machine according to the invention comprises an infusion chamber enclosed inside a containing structure and defined by two parts, respectively upper and lower, which can be selectively coupled together during the operating steps of the cycle to prepare the coffee.
Both these parts, upper and lower, are able to be associated with filter means.
According to the invention, the lower part is made on a trolley movable on a substantially horizontal plane from a first, inner position, in which it is arranged in co-operation and below the upper part, to a second, outer position, in which the lower part is removed from the upper part and emerges from the structure of the machine to facilitate the operations to load the new portion of coffee.
In a preferential embodiment, the trolley has motorised drive means. According to a variant, it is moved manually.
The upper part is made on a block movable in a vertical direction able to assume a first, raised position, during the insertion/removal steps, and a second, lowered position to close the infusion chamber during the step to prepare and deliver the coffee.
According to one characteristic of the invention, the machine to produce espresso coffee can be alternatively configured with an infusion chamber for pre-packed portions of the wafer type, or with an infusion chamber for portions of the capsule type.
According to the invention, the pre-packed portions are inserted into the infusion chamber by removing the trolley from inside the structure of the machine, in order to deposit the pre-packed portion on the lower part, and then by returning the trolley to its inner position in order to arrange the lower part in co-operation with and below the mating upper part.
It is extremely easy to deposit the pre-packed portion because the lower part is completely accessible when the trolley is in its outer position; and, once it has been returned to the inner position, it automatically causes the correct positioning and centering of the pre-packed portion inside the infusion chamber.
According to another characteristic of the invention, the machine comprises expulsion means able to automatically remove the used pre-packed portion from the lower part during the movement of the trolley as it exits from inside to outside the machine.
Thanks to the expulsion means, therefore, it is possible to avoid the manual removal of the hot used pre-packed portion, and to facilitate the insertion of a new pre-packed portion into the infusion chamber, since the lower part is already free and ready to accommodate the new portion.
According to one embodiment of the invention, the movement of the trolley to the inner position, to insert a new pre-packed portion inside the infusion chamber, causes the used pre-packed portion to be automatically discharged from the coffee machine and unloaded into collection means provided for this purpose.
According to another characteristic of the invention, the vertical movement of the block defining the opening/closing of the infusion chamber is automated and occurs in co-ordination with the execution of the cycle to prepare the coffee.
According to a preferential embodiment, the block is moved by exploiting the hydraulic thrust generated by the forced circulation of water inside an appropriate delivery circuit connected to the main circuit which delivers the water from which the coffee is made.